Page 85 - Zero Net Energy Case Study Buildings-Volume 2

ity and chemical of concern) that is being used to monitor indoor air quality. This is part of the package being offered to prospective tenants who value basic principles of sustainability in their office space.
The discovery after ten months of building operation that one of the solar PV inverters was not recording production data indicated the need not only for continued commissioning activity dur- ing the early post-occupancy period, but also for assignment of knowledgeable staff to monitor data that is being produced by the system in order to make it actionable.
Post Occupancy: HVAC and Commissioning
The initial tenant in the space decided that its conference rooms should be located at the interior of the building, rather than at the perimeter as prescribed in the building’s ZNE passive systems “drivers’ manual”. (The tenant’s reason is to provide full access to the openable windows for staff at workstations.) As a result, outside air for cooling would not ordinarily reach these interior spaces without a separate system. Engineers added transfer ducts so that the cooling air could reach into these conference rooms and provide adequate fresh air and cooling.
As noted, separate commissioning was not required because of the commitment of the design- build team to the success of the ZNE design as well as the engagement of the master system integrator from design through post-occupancy.
Post Occupancy: Lighting
As noted in the discussion of the skylights and lighting design for this case study building, the design provides enough daylight on bright days for general illumination of the office space but ordinarily would be combined with task lighting at the work surface as part of the “ambient/task” approach to lighting design in this building. For this reason, the LED light fixtures are spaced apart to provide the same general level of lighting when daylight is not available.
The tenant, however, has a typical “tech company” environment with computer monitors at sim- ple tables and their staff prefer not to use task lighting at the desks. Rather, they override the electric light fixtures in order to keep them turned on at all times and reduce the perceived varia- tion of daylighting. The combination of the LED lights at wide spacing and the daylight monitors provides a largely even lighting with only a small variation through the day provided by the day- lighting.
The tenant reports that for continuous work on computer monitors, discernible light variation ac- tually leads to migraine headaches in some cases and the constant low-level light from the LED fixtures successfully mitigates this effect from the daylight variation. The relatively high efficiency of the LED light sources apparently does not create a significant energy “penalty” for the build- ing’s overall performance.
Post Occupancy: Occupant Behavior
The monitoring of the plug loads in tenant space provided an alert to the new tenant that a batch of its equipment was using excessive amounts of energy compared to energy-efficient alterna- tives. The tenant realized that replacement of their older equipment, which was driving the high energy consumption, would be a cost effective action and developed a plan to do so.
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SPECULATIVE OFFICE BUILDING AT 435 INDIO WAY
CASE STUDY NO. 9